This invention relates to automatic packaging machines, and more particularly to machines for packaging very light particulate matter.
Reference is made to U.S. Pat. No. 4,856,566 which shows some of the aspects that are shown in this disclosure. That patent cites, as prior art the following U.S. Pat. Nos. 1,666,931; 2,910,212; 4,514,954, and U.S.S.R. Patent 735,492.
There are many different kinds of products which might be packaged by the inventive machine. However, to provide a specific example, one might refer to certain infant cereals, such as pabulum, for example. This cereal is comprised of flakes which are, perhaps, between about 1/8 and 3/16 of an inch in diameter and which are thinner than a sheet of typing paper. Particulates this light and fluffy almost float in the air, falling relatively slowly, when poured, so that they scatter if subjected to turbulent air. On the other hand, these same particulates tend to form a relatively dense and compact structure when they are resting in a pile or are sliding in bulk through a tube, because almost no air is trapped within the pile as it settles. A bulk lot of the particulates tends to plugs a tube while sliding through it, much as a piston closes a cylinder while sliding through it.
When this type of material is packaged, there is a unique and a substantial problem since the air movement caused by pouring the light particulate material causes it to fly away and scatter over a wide area. On the other hand, pouring this kind of a cereal into a box causes it to plug the box and act as a piston sliding down a cylinder formed by the box wall, which compresses air in the bottom of the box. As the density of the compressed air increases, there is a blow back which puffs the falling particulates out of the box. As a result, the usual packaging machine for such a material has a layer of particulates laying over everything within a close area.
This problem results in a potentially insanitary condition which requires a continuous clean up if the particulates are food particles, as with pabulum. It also results in a great variation in the weight of boxes. This is expensive since it becomes necessary to package enough particulates so that the lightest box still contains the posted weight, which means that the particulate material is being given away free in the heaviest boxes. Forms of particulate materials other than foods present different considerations, but the general principles are the same. It is difficult to pour many substances into a box without scattering that substance over almost everything in sight.
Accordingly, an object of the invention is to provide new and improved means for and methods of packaging particulate material. In this connection, an object is to prevent particulate material from scattering while it is being packaged. Here an object is to enable air to escape from a box while a light, fluffy particulate material is being poured into it during packaging.
Another object of the invention is to provide new and novel loading means for giving greater flexibility in the described form of packaging wherein packaging may be by either weight or volume, and may be varied quickly and easily by making only a few relatively simple adjustments.
Still another object of the invention is to provide packaging machines of the above described types which lend themselves to computerized controls so that they lend themselves to future improvement.
In keeping with an aspect of the invention, these and other objects are accomplished by providing an automatic packaging machine having volumetric cups which may be made larger or smaller responsive to either manual of electronic command signals. As boxes approach a fill station, they may tip to the side so that the particulate material, in effect, rolls down a side of the box, allowing air to escape without being entrapped in the bottom of the box.